水泵水轮机无叶区内部流场及压力脉动分析

对于高水头混流式水泵水轮机而言,其运行过程中的机组不稳定性主要源于机械内部的水力振动,而无叶区压力脉动作为其水力振动的主要原因,在一定情况下会引起机械的疲劳失效.本文通过数值模拟与模型试验相结合的方法对水泵水轮机模型在水轮机运行工况下无叶区内部流场和压力脉动进行了研究,通过数值模拟对无叶区内部流场不稳定性和活动导叶与转...

Analysis on flow structures and pressure pulsation in vanelessspace of reversible pump turbine

For a high-head Francis pump turbine,the instability during operation is mainly caused by hydraulic vibrations inside the machine.As a major cause of vibrations,the pressure pulsation in the vaneless space can possibly lead to fatigue failure under certain circumstances.This paper studies the flow field and pressure pulsation in the vaneless space between the guide vanes and runner of a model pump turbine under the generation conditions,by combining numerical simulations and physical model tests.We focus on the amplitude-frequency characteristics of flow instability and pressure pulsation,and analyze their variations under different loads.We also examine the flow field in detail on a physical model using particle image velocimetry(PIV).The mechanism and development of vortices and its influence on pressure pulsation in the vaneless space are emphasized.